Abstract : Sea trials were conducted on the first production 49-FT BUSL (49403) in August and September of 1997. The trials consisted of speed/power, tactical measurements. spiral maneuver, zig zag maneuvers, bollard pull, noise and vibration survey, endurance test, emergency stop, scale weighing, and an initial corrosion survey. The BUSL met all of its on-board noise requirements. The steering trials demonstrated that the 49403 had very good directional stability and good rudder responsiveness. It was determined that little additional speed was gained for the fuel expended when running at engine rpms above 2300 rpm. Derating the engine from 2500 to 2300 rpm will save fuel costs while retaining a top speed of 10 knots. The 49403 achieved a bollard pull of 11,000 lbs. and 8,300 lbs. when pulling from the aft and the bow, respectively.